All kind of switch has mechanical contacts. The most basic of contacts is NC type contact ( Normally Close ) and NO type contact ( Normally open ). Some switch has only 1 NC contact , some switch has only 1 NO contact , and some model consist of many contacts ; NO NC Common terminals. The circuit diagram of switch has printed on its body. How to check switch it depends on contact type of witch.
Basic output contact form consists of NC and NO contact
Step to check switch
1. Turn rotary switch to continuity test function of digital multimeter.
2 Connect test leads to the NC contact of switch. The meter will beep if it is a good NC contact. Bad NC contact , the meter does not beep. After that change switch position by pressing to ON and OFF. The good contacts will change status from ON to OFF or OFF to ON.
3. Connect the test leads to the NO contact. The meter will not beep if it is a good NO contact. Bad NO contact , the meter will beep ( short circuit).
After that change switch position by pressing to ON and OFF. The good contact will change status from OFF to ON and ON to OFF. These changing of contact represent results on multimeter display.
4. Test every NO and NC contact set. If there is only 1 contact is bad , the switch is not good.
then find the replacement.
Then change the toggle position , the NC contact connection will change too, from beep to OL
2 Connect test leads to the NC contact of switch. The meter will beep if it is a good NC contact. Bad NC contact , the meter does not beep. After that change switch position by pressing to ON and OFF. The good contacts will change status from ON to OFF or OFF to ON.
3. Connect the test leads to the NO contact. The meter will not beep if it is a good NO contact. Bad NO contact , the meter will beep ( short circuit).
After that change switch position by pressing to ON and OFF. The good contact will change status from OFF to ON and ON to OFF. These changing of contact represent results on multimeter display.
4. Test every NO and NC contact set. If there is only 1 contact is bad , the switch is not good.
then find the replacement.
Test NC contact of switch , the meter will beep if it is a good NC contact.
Bad NC contact , the meter will not beep.
Bad NC contact , the meter will not beep.
Test NC contact of switch , the meter will beep if it is a good NC contact.
Represent as beep for connected and OL display for disconnected.
Read more of testing , list of article here .
